A window washer who does not want to change his position will want the forces acting on him to be

a. balanced.

Explanation:

The options for this question are

a. balanced

b. large

c. small

d. unbalanced

Basically, the situation described involves a balanced system, that is, according to Newton's Law, the sum of all forces, that are applied on the object, is null. In other words, all forces involved cancel each other, because they the same but opposite, like adding and subtracting the same number.

Having said that, if an object doesn't move while a force act on it, that means such object is balanced, like this case.

Therefore, the right answer is a. balanced.